Exemplary embodiments of the present invention relate to air cycle machines and, more particularly, to a thrust plate assembly for an air cycle machine utilized as part of an aircraft environmental control system.
Conventional aircraft environmental control systems (ECS) incorporate an air cycle machine (ACM), also referred to as an air cycle cooling machine, for cooling and dehumidifying air supplied to an aircraft cabin. ACMs commonly include at least one turbine and a compressor spaced axially at intervals on a common shaft. The turbine(s) and compressor are supported for rotation about the axis of the shaft by one or more bearing assemblies.
On aircraft powered by turbine engines, the air to be conditioned in the ACM is typically compressed air bled from one or more compressor stages of a turbine engine. In conventional systems, this bleed air is passed through the ACM compressor, where it is further compressed, then passed through a condensing heat exchanger to cool the compressed air. The heat exchanger sufficiently condenses moisture thereby dehumidifying the air. The dehumidified compressed air is then expanded in one of the turbines to extract energy from the compressed air so as to drive the shaft and also to cool the expanded turbine exhaust air as it is supplied to the cabin as conditioned cooling air.
ACMs often have a three-wheel or four-wheel configuration. In a three-wheel ACM, a turbine drives both a compressor and a fan which rotate on a common shaft. In a four-wheel ACM, two turbine sections drive a compressor and a fan on a common shaft.
Airflow must be directed into the fan section to the compressor section, away from the compressor section towards the heat exchanger, from the heat exchanger to the turbine or turbines, and from the final turbine stage out of the ACM. In at least some of these transfers, it is desirable to direct air radially with respect to the central axis of the ACM. To accomplish this, nozzles may be used to generate radial in-flow and/or out-flow.
To contain and route airflow through the ACM, components of the ACM must be designed to balance operational efficiency, internal cooling, and reliability. Reduced airflow and internal leakage can increase loads on certain ACM components, while increased internal leakage can lower operational efficiency and increase fuel consumption.